Among the top tier of games in the GBA library.
Advance Wars 2: Black Hole Rising does not have big time marketing backing it, but it has consistently been one of the top sellers among GBA games for one reason: it is addictive and fun. Featuring a turn-based battle system that is much more involving and fun than turn-based games usually are, the game is rich with personality and style. Advance Wars 2 is easy to recommend to anyone with even a passing interest in strategy or war games.
This game is great if you're looking for something for a short stint with the GBA, a sit-down-and-play-for-15-minutes type of game, but also boasts something to offer the serious gamer, since with a lot of time you can plow through several battles - or more likely, retry one a few times to get an "S" rank, the highest attainable with victory. Various types of campaigns and battles will keep your interest piqued for a long while, and there is a huge amount of replayability to this game.